In the Third Generation Partnership Project (3GPP) System Architecture (SA) Working Group Stage 2 Meeting #112 (SA2#112), it was pointed out that there may be an issue related to the Tracking Area Identity (TAI)—List handling in the Mobility Management Entity (MME) (see 3GPP Technical Report (TR) 23.714, clause 6.1.1.7). With the user plane functionality separation from the control plane functionality in the Evolved Packet Core (EPC) Serving Gateway (SGW)/Packet Data Network (PDN) Gateway (PGW), multiple EPC SGW/PGW user plane functional entities (referred to herein as SGW-Us) may be controlled by a single SGW/PGW control plane functional entity (referred to herein as a SGW-C). Therefore, the MME will be unable to assess if the Tracking Area (TA) that the User Equipment device (UE) is currently entering can be added to the TAI List of the UE (also referred to herein as a TA list).
The problem is actually more general than just handling the TAI List in the MME, and the issue coincides with problem of assessing if the SGW-U needs to be re-allocated at mobility to a new TA. In other words, the question becomes whether the new TA is served by the SGW-U currently allocated by the SGW-C or not. The issue is illustrated in FIG. 1. When the UE moves from TA2 to TA4, the MME cannot know if the new TA (i.e., TA4) is served by the same SGW-U or not and cannot know if the new TA (i.e., TA4) can be added to the TAI List of the UE. As such, there is a need for a system and methods that address these problems.